Master intermediate-level SQL concepts such as views, functions, indexes, and advanced data handling to confidently ace interviews for experienced SQL roles.

SQL Interview Preparation - Intermediate (2).png

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MySQL

MySQL-withoutT

Ready to stand out in your next SQL interview? This course is your ultimate guide to mastering intermediate—and advanced-level SQL concepts. It will help you write efficient queries and tackle even the toughest interview challenges.

The course is designed for candidates with prior MySQL experience and takes you step-by-step through real-world SQL problems. You’ll start with database management basics like creating and deleting databases, then move on to important concepts such as views, aggregate functions, and indexes. As you progress, you’ll master advanced SQL techniques, including stored procedures, string comparisons, regular expressions, and cross joins. In the final stretch you’ll learn about ranking functions, analytical functions, and complex subqueries—key topics in senior-level SQL interviews.

Walk into your interview with confidence and secure your next SQL role!

SQL Interview Preparation—Intermediate Level

/* The query to use UNION ALL to combine result sets */
SELECT    e.EmpID, e.EmpName, s.SkillName, p.ProjectName 
FROM      Employees e 
LEFT JOIN Skills s ON e.EmpID = s.EmpID 
LEFT JOIN Projects p ON e.EmpID = p.EmpID OR s.SkillID = p.SkillID 
UNION ALL 
SELECT    e.EmpID, e.EmpName, NULL AS SkillName, NULL AS ProjectName 
FROM      Employees e 
WHERE     e.EmpID NOT IN (SELECT DISTINCT EmpID FROM Skills) 
AND       e.EmpID NOT IN (SELECT DISTINCT EmpID FROM Projects)
ORDER BY  EmpName DESC;

Find a detailed explanation of set operator UNION ALL.

Get Started

Managing Databases

Views

Indexes

Stored Procedures

Complex Data Handling

Set Operators

Ranking and Analytic Functions

Window Functions

Subquery

Final Remarks

Answer: UNION ALL Set Operator

Solution

Code explanation